Low-latency start-up for a monolithic clock generator and timing/frequency reference

Abstract

An apparatus, system and method are provided for low-latency start-up of a free-running harmonic oscillator. The exemplary apparatus embodiment comprises a first and second current sources to generate first and second currents; a bias current monitor adapted to detect a magnitude of the second current and to provide a control signal when the magnitude of the second current is equal to or greater than a predetermined magnitude; and a bias controller adapted to switch the first current from the oscillator and to switch the second current to the oscillator in response to the control signal. a reference voltage generator, a comparator, and a bias controller. Exemplary embodiments include reference voltage generator, a comparator, and a bias controller.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation-in-part of and claims priority to U.S. patent application Ser. No. 11 / 084,962, filed Mar. 21, 2005, inventors Michael Shannon McCorquodale, Scott Michael Pemia, and Amar Sarbbaseh Basu, entitled “Monolithic Clock Generator and Timing / Frequency Reference” (the “first related application”), which is commonly assigned herewith, the contents of which are incorporated herein by reference, and with priority claimed for all commonly disclosed subject matter, and further claims priority to U.S. Provisional Patent Application Ser. No. 60 / 555,193, filed Mar. 22, 2004, inventor Michael Shannon McCorquodale, entitled “Monolithic and Top-Down Clock Synthesis with Micromachined Radio Frequency Reference” (the “second related application”), which is commonly assigned herewith, the contents of which are incorporated herein by reference, and with priority claimed for all commonly disclosed subject matter. [0002] This a...

AI Technical Summary

Benefits of technology

[0011] In addition, the various exemplary embodiments of the invention provide a clock generator and/or a timing and frequency reference having multiple operating modes, including modes such as a power conservation mode, a clock mode, a reference mode, and a pulsed mode. In addition, the various embodiments provide multiple output signals at different frequencies, and provide low-latency and glitch-free switching between these various signals.

[0012] Significantly, the various exemplary embodiments of the invention generate a signif...

Problems solved by technology

The difficulty with such crystal oscillators is that they cannot be fabricated as part of the same integrated circuit (“IC”) that is to be driven by their clock signal.

For example, because such a processor must be connected through outside circuitry (such as on a printed circuit board (PCB)), power dissipation is comparatively increased.

In applications which rely on a finite power supply, such as battery power in mobile communications, such additional power dissipation is detrimental.

In addition, such non-integrated solutions, by requiring an additional IC, increase space and area requirements, whether on the PCB or within the finished product, which is also detrimental in mobile environments.

Moreover, such additional components increase manufacturing and production costs, as an additional IC must be fabr...

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